The present invention relates to the manufacture of corrugated paperboard for use in structural applications in which waterproofing is imperative. More particularly, the invention pertains to a method and apparatus for converting corrugated media and liner webs impregnated with an A-phase phenolic resin and dried to a partially cured B-phase to produce a fully cured C-phase waterproof single face corrugated web.
U.S. patent application Ser. No. 11/769,879, filed on Jun. 28, 2007, which is incorporated herein by reference, describes a method and apparatus for manufacturing open core elements from paperboard webs for applications which might include exposure to water and high humidity. In such applications, the paperboard web must be treated to prevent damage and loss of strength in the presence of water. The hollowcore elements produced in accordance with the above identified patent lend themselves to many structural applications, including relatively narrow structures such as doors and much wider and deeper structures such as walls, decks, floors and beams.
One advantage of the method described in the above identified application, in addition to the broad flexibility of the process, is the high output attainable by the unique method for laying up the open core elements. If a waterproof paperboard web is required, it is important that the waterproofing process is fast and accurate enough to fit into the lay-up process without loss of time and quality.